Smectite clays, also known as water-swellable layered silicates, are dispersible in water but not in hydrophobic liquids. In contrast, hydrophobically-modified smectite clays, often referred to as organoclays, are dispersible in hydrophobic liquids but not in water. Overcoming the limitation of poor aqueous-dispersibility of organoclays would enable these hydrophobically surface-modified clays to reach new frontiers of clay-based technologies. The present invention fills this void, revealing compositions and methods for rendering organoclays water-dispersible.
Smectite clay particles are plate-like particles (hence referred to herein as platelets), having face (basal) and edge surfaces. Organophilic smectite clays are the hydrophobically surface-modified smectite clays, a portion of whose surface is switched from being hydrophilic to hydrophobic, by adsorbing hydrophobic surface-modifying agents onto the platelet surface. The surface-modifier can be a surfactant, for example, an alkyl quaternary ammonium compound, preferably with C8-C22 alkyl chain(s), or a hydrophobic polymer.
Being dispersible only in hydrophobic liquids or oil phases, organoclays are always included in the “oil”- or hydrophobic-phases of compositions used in various industrial applications and consumer products. These compositions can be anhydrous compositions, or oil-in-water emulsions, or water-in-oil emulsions. Ordinarily, when mixed with water (even under high-shear mixing), the organoclays would invariably show a high level of particle agglomeration, with the agglomerated particles visibly appearing in the form of lumps or clusters.
Using organophilic clays in water-based applications hitherto has not been possible, since the prior art does not contain teachings as to how to optimally disperse these clays in water, wherein the clay platelets could then effectively provide for a targeted benefit. For example, it might be possible to use organoclays as surface-conditioning agents, as in hair-conditioning and fabric-softening, if they could be dispersed in water-based compositions such as shampoos, conditioners, detergents, and fabric-softeners.
The aforementioned void in the prior art hitherto has prevented the use of organoclays in applications requiring water-based dispersions of organoclays. Therefore, compositions, wherein organoclays can be adequately dispersed in aqueous solutions, would greatly facilitate developing novel applications for organoclays. An object of the present invention is to provide these compositions.